Functional magnetic resonance imaging was used to study brain activity in 3-to 5-year-old children as they listened to age-appropriate stories. The researchers found differences in brain activation according to how much the children had been read to at home. Children whose parents reported more reading at home and more books in the home showed significantly greater activation of brain areas in a region of the left hemisphere called the parietal-temporal-occipital association cortex. This brain area supports mental imagery and narrative comprehension. Children who were exposed to more books and home reading showed significantly more activity in the areas of the brain that process visual association, even though the child was in the scanner just listening to a story and could not see any pictures.